My stock spring was highly worn because of accidental dry fires, so I got this spring kit. Honestly, not too much of a difference. Oh, did I mention they come in colors? :P If you have ten bucks go out and fill your air/CO2... Not worth it unless you have a bad spring.

Conclusion:

I couldn't tell the difference when I shot. So save your cash and get some air or paint.
5 for average. It did what it was supposed to. I guess.